Before people ever made it to the South Pole, a pollutant had beaten us there

In 1911, Norwegian Roald Amundsen and British Navy officer Robert Falcon Scott were racing to be the first humans to reach the South Pole. But even before Amundsen made it there and planted his flag, humankind had already made an impact on this isolated spot. The pollution that humans created traveled faster than either Amundsen or Scott and reached the pole before any explorer.

More than 100 years after Amundsen won the race to the South Pole, my research group found that industrial pollution had reached Antarctica more than 20 years before... Thousands of kilometres away, a source of lead, zinc, and silver had been discovered in 1883 at Broken Hill in Australia. Mining and processing operations began soon after, and smelting began at nearby Port Pirie in 1889.

Scott and Amundsen were travelling over apparently untrammelled snow that was in fact heavily contaminated from smelting and mining in Australia, with lead pollution at the time almost as high as at any time since.

It's a stark juxtaposition of humanity's less uplifting activities—polluting not only the places we've settled but places we haven't even been yet—and its more inspiring ones, like exploring.

In all, 660 tons of lead have reached Antarctica in the last 130 years, the study notes. The levels of the toxic heavy metal in the ice core samples that the scientists studied peaked in 1900—although they remained high until the Great Depression and started gradually increasing after World War II. It was only in 1990, when laws reducing the use of lead in gasoline and other fuels began to take effect, that the lead levels started declining again. Even today, the lead levels in the Antarctic snow remain four times higher than they were before industrialization.